As one of complications after laparotomy surgery in abdominal surgery, gynecology and the like, there is an adhesion of organs. This may be caused in a wound healing process of surgery by reformation while tissues that essentially should not be in contact are brought into contact with each other, and this is known as adhesion. It is said that adhesion is caused at a high possibility in a laparotomy surgery, but many are asymptomatic. Although not frequent, adhesion may lead to pain or serious complications such as ileus or sterility.
Since once formed adhesions cannot be treated non-invasively, when having severe complications such as ileus, there is only surgical operation to peel off the adhesion site and, therefore, it is extremely important to firmly carry out a treatment of the wound site aimed for prevention of adhesion after initial surgery.
Conventionally, as a material having an adhesion-preventing effect, a method of using silicon, “Teflon (registered trademark),” polyurethane or the like as an adhesion-preventing material to physically separate organ tissues has been performed. However, because these materials are non-bioabsorbable materials, they remain on the surface of the biological tissue, and not only do they delay repair of the tissue, but also they cause infection and inflammation.
In recent years, to solve such problems, adhesion-preventing materials using natural polymers such as gelatin or collagen which can expect bioabsorbability are reported (for example, JP 2004-065780 A and JP 2001-192337 A). However, because gelatin and collagen have a problem in that it is difficult to remove a telopeptide part having an antigenicity and, further, there is a risk of infectious diseases derived from organisms such as prion contamination, it is better to avoid using to an organism. Moreover, there are many cases where a crosslinking agent added to obtain strength and control degradability is not preferred for use in an organism.
In a natural polymer, there is such a problem that it is low in strength though it is high in affinity with skin. Therefore, in a natural polymer, it has been necessary to ensure strength by a material crosslinked with a crosslinking agent or by use of a reinforcement material or by wrapping with a gauze. When a reinforcement material is used, because there are many cases where the structure becomes complicated, it is not practical.
Further, there is also a report on adhesion-preventing materials using polysaccharides such as trehalose and sodium alginate, which are low in risk of infections (for example, JP 2003-153999 A). However, since there is a problem that polysaccharide film materials cannot reliably cover the wound site because of rupture or the like due to lack of strength, they are low in practical use. Among polysaccharides, there is a report on adhesion-preventing materials using hyaluronic acid (for example, WO 2005/094915 A1). Since hyaluronic acid is high in water solubility, it absorbs moisture in the body and gels, but because the gel moves in the direction of gravity with time, there are problems that an effect cannot be obtained because sufficient ingredients do not remain in the affected area, and that bacteria proliferate in the gel pool accumulated by moving in the direction of gravity and may cause infection.
Furthermore, to strongly adhere the adhesion-preventing film to the organ and the like, although there are a method for using blood products and a method for using chemical substances, those methods include a problem that a high-quality management in viewpoint of safety is required and it is difficult to be handled.
In addition, as a method excellent in adherence with the affected part and can suppress movement in the direction of gravity, although a polymer structure in which a biodegradable resin layer of polylactic acid or the like and a water-soluble resin layer are laminated has been proposed, control of solubility of the water-soluble resin and handling property (stickiness) at the time of surgery was not sufficient (for example, JP 2012-187926 A).
Thus, although there are many reports relating to materials to prevent tissue adhesion, a material having a satisfactory performance as an adhesion-preventing material has not been obtained. Namely, a material, being hard to cause the above-described problems and capable of preventing adhesion until a tissue is recovered and maintaining a sufficient strength until the tissue is recovered, is required.
Especially in recent years, although laparoscopic surgery and endoscopic surgery are increasing to alleviate the physical burden of patients in surgical operations, conventional sheet-like adhesion-preventing materials are difficult to be passed through the inside of a tube (drain) placed in the horacic cavity and used for treatment of pneumothorax, pleural effusion, empyema and the like such as a trocar and, further, in a liquid adhesion inhibitor, there is a problem of poor coatability because it is poor in flowability.
It could therefore be helpful to provide a polymer film which is easy to handle and excellent in followability, coatability, adhesiveness and adherence to organ tissues, and a dispersion liquid and an agglomerate using the same.